Automatic reclosing circuit breaking system



Their Attorney.

Inventors Edward E. Bauer Anton W. Fr

E. E. BAUER ETAL Filed Feb. 3; 1942 AUTOMATIC RECLOSING CIRCUIT BREAKING SYSTEM Sept. 28, 1943.

rent transformer 6.

Patented Sept. 28, 1943 AUTOMATIC REOLOSING CIRCUIT BREAKING SYSTEDI c Scnipany, a corporation of New York Application February 3, 1942, Serial No. 429,416

Claims. (Cl. 175-294) Our invention relates to automatic reclosing circuit breaking systems and particularly to such systems in which, in case of a permanent fault, a circuit breaker is automatically reclosed a predeterminednumber of times with predetermined time intervals between each opening of the circuit breaker and the next reclosure thereof.

One object of our invention is to provide a new and improved arrangement of apparatus for effecting, in case of a permanent fault, an instantaneous first reclosure of the circuit breaker and a predetermined number of subsequent time delayed reclosures before the circuit breaker is permanently locked out.

Our invention is an improvement in the arrangement disclosed in'United States Letters Patent 2,059,836 granted November 3, 1936, and assigned to the'same assignee as this application whereby each opening of the circuit breaker causes a charged condenser to be discharged through a suitable relay, which in turn is arranged to effect the reclosure of the circuit breaker.

Our invention will be better understood from the following description when taken in connecload circuit 3. The circuit breakerl may be of any suitable type, examples of which are well known in the art. As shown in the drawing, the circuit breaker is'of the wellknown trip-free latched-in type comprising a closing coil 4 and a trip coil 5 wherebya predetermined energization of the trip coil 5 eifects the opening of the circuit breaker irrespective of the energization of the closing coil 4 and the circuit breaker is prevented from being closed again until after the closing coil 4 has been deenergized.

Any suitable fault-responsive means may be provided for effecting the opening of the circuit breaker I when a fault occurs on the load circuit 3. For accomplishing this result, we have shown the trip coil 5 as being connected in series relation with the load circuit 3 by means of a cur- The trip coil 5 is arranged so that it cannot eifect the opening of the circuit breaker I until a predetermined abnormal current flows through the load circuit 3;

For effecting the reclosure of the circuit breaker I when it is opened in response to a fault on the load circuit 3, we provide a condenser 'I,

which is shown permanently connected to a suitable source of direct current 9 with a relatively high resistance 8 connected in series therewith. The resistance 8 is so designed that it permits the condenser l to be charged at a predetermined rate. I0 represents a relay having an operating winding II, which is arranged to be connected across the condenser I whenever it is desired to reclose the circuit breaker I. The closing of the contacts I2 of the relay I0, whenever the circuit breaker I is open, completes an energizing circuit for a control relay I3, which when energized completes an energizing circuit for the closing coil 4 of the circuit breaker I.

In response to the initial opening of the circuit breaker I, when a fault occurs on the load circuit 3, an energizing circuit for the operating coil II of the relay II] is immediately completed across the condenser! so that an immediate reclosure of the circuit breaker I is effected by the closing of the contacts I2 of the relay I0. At the same time, the closing of the contacts I6 of the relay I0 effects the completion of an energizing circuit for a holding winding I! of the relay I0 through the contacts 30 of the circuit breaker I so as to insure that the relay I0 remains in its energized position until the circuit breaker I is closed. The closing of the contacts I6 of the relay I0 also effects the energization of an associated control relay I8 so that it opens its contacts IS in the original energizing circuit of the operating winding II of the relay ID in order to prevent this energizing circuit from being completed in case the circuit breaker I is opened immediately after its first reclosure. The opening of the contacts I9 also allows the condenser again to be recharged by the source 9.

The next reclosure of the circuit breaker I, in case the fault is of such a character that it effects an opening of the circuit breaker within a predetermined time after the first reclosure thereof, is effected by means of atime relay 20 closing its contacts 2| in an energizing circuit for the operating-Winding II of the relay I0 across the condenser E. The time relay 20, which preferably has an adjustable operating time, is so connected that it is set into operation at the time of the first reclosure. The closing of the contacts 22 of the time relay 23 effects the energization of an associated control relay 23, which by closing its contacts 24 effects the energization of an associated time relay 25, which preferably has an adjustable operating time, and an associated control relay 2c. By opening its contacts 2?, the relay 23 prevents the operating coil II of the relay Ill from being energized in case the circuit breaker I is opened immediately after the second reclosure, and allows the condenser l to be recharged by the source 9.

The third reclosure of ;.the circuit breaker I; in case the" fault is of such a character that it effects an opening of the circuit breaker l within a predetermined time after the second reclosure thereof, is elfected by the time relay 25 closing its contacts 28 and thereby completingan'energizing circuit for the operating Winding I I of the relay Iii across the condenseri. In. response to the third reclosure of the circuit breaker I, the relays 23, 25, and 26 are deenergized so as to restore the control devices to their normal conditions. In this manner, the operating Winding II of the relay It! is arranged to be immediately connected across the condenser 1 in response to thenext opening of the circuit breaker I. There- 7 fore, if the circuit breaker I.- is opened immedi- .ately. afterthe third reclosure so that the operating :winding. II is connected'across the condenser. Ibefore it has-had time to become sufiiciently rechargedafterthe third reclosureto efiect the operation of the relay. It], no further automatic reclosures of the circuit breaker can beeffected'. vI-Ioweyer,if the circuit breaker I re- ;mains closedafter the third reclosure for a suffi cient length of time to allow the condenser I to become fully recharged, the next reclosure of the circuit-breaker I. will occur immediately after the next opening thereof. and. the arrangement will proceed through at normal sequenceof operation.

Theoperationrofythe arrangement shown in the qdrawingu-ispas follows: xWhen the circuit ,bre'aker his-closedso-that-the auxiliary contacts-.45; thereof .are open,ithe condenser I is chargedata rategdependent upon the size of the resistance 8 and the capacity of the condenser. I. After the..-ci rcuit breaker 'I has remained closed for a predetermined timethe condenser 'I be- *comesiully charged so that the voltage across its terminalsyis substantially equal to the voltage of the charging -source.

1 It -;wil1 inoW be-assumed that after the condenser "I 'has become' fully charged a fault occurs ;on-.the load; circuittwhich causes sufi'icient cur- -;rent 'tOlfiOW through the trip coil" to effect the pening-Of' the circuit breaker 'I. The closingof the-auXiliary-contactsI 5 of'the circuit 'breaker I :conn'ects ltheioper'ating win'ding II of the relay IO,-,'=the contacts 2! of the relay23, and. the contacts; I 9 of the. :relayxIB :ina series circuit across the terminalsofthe condenser 'I so that the-congdenser'startslto discharge through therelay winding M. 'gThe-itime. it itakesfthe condenser to ,dischargeedepends.:onx'the constants of the :circult -through:. the relay i-win'din g-but the relay windingi i; is soidesigned that the condenser "I becomes :gsubs'tantially 'discharged before the windingxis:disconnected'therefrom. The voltage across the'condenserr 'l.'at' 'the'instant the relay WindingpII a'is connectedin parallel with it is 'suflicient t'o cause the relay -II! 'to close immediatlykits"contacts-i2 and I6. By closing its contacts 1 6,- the relay' I0 completes an energizing circuit 'fo'r "its ho'lding'winding IIfthrough the auxiliary'contacts 38, of the circuit breaker I. The closing of the contacts it of the relay Iilalso completes "through contacts 3! of the relay 26 energizingcircuitsfforjthe controlrelay I8 and source 9.

the time relay 243. By closing its contacts 32, the relay I8 completesthrough the contacts 33 of the relay 23 a locking circuit for itself and another energizing circuit for the time relay 26. By opening its contacts I9, the relay I8 opens the original energizing circuit of the relay winding I I so that this relay winding cannot be immediately i'e energized in case the circuit breaker I opens immediately after the first reclosure thereof, and so that the condenser I is again recharged by the vBy closing its contacts I2, the relay I9 completes through the auxiliary contacts 34 on the circuit breaker I an energizing circuit for the control relay 53, which in turn by closing its contacts 35 completes an energizing circuit for the closing coil 5 to eiTect a reclosure of the circuit, breaker I. The opening of the auxiliary contacts as on the circuit breaker I, when it closes, interrupts the energizing circuit of the -holding winding II of the relay II] so that it is restored to its normally deenergized position.

if after its first reclosure the circuit breaker I is opened by the trip coil 5 any time before the time relay 2! completes its timing operation, the closing of the contacts fil. of the relay 2.8, when it completes itstiming. operation, connects the operating winding II of the relay II) and the auxiliary contacts: I5 of the circuit breaker I across the condenser I.

The operating time of the time relay 26 is adjusted so that it is longer than the chargingutime of the condenser I, and therefore the relay It! is energized to eiiect a second reclosure of the circuit breaker. I in the .same manner as-it efiected the first reclosure.

The closing of the contacts'22 of the time relay it! completes an energizing circuit for the control relay 23, Which by, closing its contacts 917.com- .pletes a lockingcircuit for itself through the contacts .38 of the time relay 25. "Byopening its .contactsfi'Lthe relay-'23 interrupts the initial energizing circuitflof the relay .winding II, and

by opening its contacts 33, the relay 23 effects the deenergization of; the control relay I8 and. the time relay'2il so that they are immediately restored to their normally deenergized positions. By closing its contacts 24, the relay'23 completes anenergizing circuit for the time relay 25 and also anzenergizing circuit for the control relay .er 'I is opened by the trip coil 5 any time before the time relay'25 completes its timing operation,the closing of the contacts28 of the relay 25, when it completes its timing operation, connects the operating Winding H of the relay I 0 and the auxiliary contacts :I5 of the circuit breaker I in series across the condenser I. The time relay =25-is adjustedso that its timing operation is longer than the charging time of the condenser I. Therefore, the relay II] is sufficiently energized to eiTect-the third reclosure of the circuitbreaker! in the same .manner as it effected the -first and second reclosures.

The opening of the contacts :38 of the time relay-25 interrupts the holding circuitof the relay 23 so thatit is immediately restored to its normally deenergizedposition. The closing of the auxiliarycontactsafl on the circuit breaker .I in response to the third reclosure of the circuit breaker completes a shunt circuit around the operating winding of therelay 26 so that this relay becomes deenergized and opens its contacts 40in its holding circuit and in the energizing circuit of the time relay 25 so that both of the relays 25 and 26 are also restored to their normally deenergized positions.

If the circuit breaker I opens after the third reclosure thereof and before the condenser 1 has had time to become recharged, another reclosure of the circuit breaker cannot take place because the closing of the auxiliary contacts I5 of the ,circuit breaker I reconnectsthe low impedance operating winding II of the relay I across the condenser I and therefore causes the condenser I to discharge through the relay winding I I without effecting the operation of the relay II). If, however, 'thecircuit breaker I remains closed for a sufficient length of time after the third reclosure thereof, the condenser I has time to become sufficiently recharged to effect an immediate reclosure of thecircuit breaker the next time it is opened.

If the circuit breaker I remains closed after either the first or the second reclosure, the time relays 20 and 25 are sequentially operated and then are restored to their normally deenergized positions in the manner heretofore described. The operation of the relay 2!) or the relay 25 while the circuit breaker I is closed does not effect the energization of the relay I0 because the circuit of the operating winding II thereof is opened at the contacts I5 of the closed circuit breaker I.

While we have, in accordance with the patent statutes, shown and described our invention as applied to a particular system and as embodying various devices diagrammatically indicated, changes and modifications will be obvious to those skilled in the art, and we therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, an electric circuit, a circuit breaker in said circuit, fault responsive means for effecting the opening of said circuit breaker, a normally charged condenser, a relay having a low impedance operating winding, means responsive to a predetermined energization of said relay winding for effecting the closing of said circuit breaker, means responsive to the initial opening of said circuit breaker for effecting the immediate connection of said relay winding across said condenser, timing means having a predetermined timing operation, means responsive to initial energization of said relay Winding for effecting the operation of said timing means and the immediate disconnection of said relay winding from across said condenser, means controlled by said timing means and said circuit breaker for effecting the connection of said relay winding across said condenser when said timing means completes its timing operation if said circuit breaker is open at that time, and means for charging said condenser when said relay winding is not connected thereto.

2. In combination, an electric circuit, a circuit breaker in said circuit, fault responsive means for effecting the opening of said circuit breaker, a normally charged condenser, a relay having a low impedance operating winding, means responsive to a predetermined energization of said relay winding for effecting the closing of said circuit breaker, means responsive to the initial opening of said circuit breaker for effecting the immediate connection of said relay winding across said condenser, timingmeans having a predetermined timing operation, means responsive to initial energization of said relay winding for effecting the operation of said timing means and theimmediate disconnection of said relay winding from across said condenser, means controlled by said timing means and said circuit breaker for effecting the connection of said relay winding across said condenser when said timing means completes its timing operation if said circuit breaker is open at that time, a second timing means having a predetermined timing operation, means responsive to said first mentioned timing means completing. its timing operation for initiating the timing operation of said second timing means, means controlled by said second timing means and said circuit breaker for effecting the connection of said relay winding across said condenser when said second timing means completes its timing operation if said circuit breaker is open atthat time, and means for charging said condenser when said relay winding is not connected thereto.

3. In combination, an electric circuit, a circuit breaker in said circuit, fault responsive means for effecting the opening of said circuit breaker, a normally charged condenser, a relay having a low impedance operating winding, means responsive to a predetermined energization of said relay winding for effecting the closing of said circuit breaker, means responsive to the initial opening of said circuit breaker for effecting the immediate connection of said relay winding across said condenser, timing means having a predetermined timing operation, means responsive to initial energization of said relay winding for effecting the operation of said timing means and the immediate disconnection of said relay winding from across said condenser, means controlled by said timing means and said circuit breaker for effecting the connection of said relay winding across said condenser when said timing means completes its timing operation if said circuit breaker is open at that time, a second timing means having a predetermined timing operation, means responsive to said first mentioned timing means completing its timing operation for initiating the timing operation of said second timing means, means controlled by said second timing means and said circuit breaker for effecting the connection of said relay winding across said condenser when said second timing means completes its timing operation if said circuit breaker is open at that time, means for connecting said relay winding immediately across said condenser in response to the next opening of said circuit breaker after said second timing means has completed its timing operation, and means for charging said condenser when said relay winding is not connected thereto.

4. In combination, an electric circuit, a circuit breaker in said circuit, fault responsive means for effectiing the opening of said circuit breaker, a normally charged condenser, a relay having a low impedance operating winding, means responsive to a predetermined energization of said re lay winding for effecting the closing of said circuit breaker, means responsive to the initial opening of said circuit breaker for effecting the immediate connection of said relay winding across said condenser and for effecting subsequent con- "neti ons fof said reiay'winding-across said conclement predetermined tim" rite'r vals thereafter if t the expiration off'ao'h of i said time intervals 'c'z'irciiit breaker is "openfi'mean's for charging "Said-condrlsr when said rela Winding is not "tiijneoted th'refio', ho1dingmeans for's aid relay, and means for ="r nd'en 1g said holdirig means 6p n rsponse td sai'd predetermined energ'izfi'tion 6f said one-rating "Winding 2316 While Said,

'ir'uit breakfer is been and "for" maintaining Said '(iuit bieakennieans responsive to the initial'openv -of said circuit breaker forefie'ct'ing theim- 'iiiediate connection of said relay 'wincling across said; condenser, f timing mean I having a predefiim'ih'd timifig 'OI5'efaQti6n; iflan's "IS pCin'SiVe t0 initial energization of 'saidre lay wiziding for ef- 1 v 'fectingthe 'oper atioriof s'aid timing" means and the immediate disconnection of said relaywinding from across's'aidcondenserjmeans controlled by said timing means and said circuit 'breaker for effecting the Connection of "said relay' winding across saidcondenser when said timingmeans completes its timing operation if said circuit breaker is open at that'time'a second timing means havin'g'a predetermined timing operation, means responsive to said first mentioned timing means completing its timing operation for initiat- '-ing"the'-'timing operation of's'aid second timing means, means controlled by said second timing means and said circuit breaker for'efiectingthe connection of said relay winding across said condenser when said second timing means completes its timing operation if said circuit loreaker is open a't-that time, means for chargingsaid'condenser when said relay Winding is not connected-thre to, holding means iorsaid relay; and means-for rendering said holding means operative response to said predetermined"energization of'said operating winding and while said circuit breaker is open and for maintaining said holdingmeans operative until said circuit breaker is'closed.

' EDWARD BAUER.

ANTON W. FRAPS. 

